So, I will try to ask specifically:
1. if I decide to buy airport express - i will connect it to network created with TC or airport extreme, than connect my speakers to express sound output and that is all?
2. will I be able to use my speakers (connected as stated above) with several devices (I have two macbooks, iphone...)?
3. If so, what happens when using speakers by one user/macbbok and another one tries to use the speakers as well???